Se . 
oe eer 
638 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Remarks. —We cannot place Strotocrinus and Teleiocrinus together in the 
same genus, as was done by Meek and Worthen, for they evidently have 
a different origin, the former being developed from Physetocrimus, the latter 
from Cactocrinus. The modifications that took place in the two forms were 
in the same direction, and this accounts for the resemblance which unques- 
tionably exists between them. A very interesting feature of this genus, 
which has not been observed in Teleiocrinus, is the incorporation of the 
lower pinnules, the plates of which take the form and office of interbrachial 
1866. Strotocrinus regalis —Munxk and Wortuen; Geol. Rep. Illinois, Vol. I1., p. 190. 
1873. Strotocrinus perumbrosus—MerKx and Wortunn; Geol. Rep. Illinois, Vol. V., p. 357, Plate 8, 
Fig. 4. 
1881. Strotocrinus regalis —W. and Sp.; Revision Paleocr., Part IL, p. 160. 
Syn. Actinocrinus perumbrosus — HatL; 1860, Suppl. Geol. Rep. Iowa, p. 7. 
Syn. Actinocrinus speciosus Manx and WortHEN; 1860, Proceed. Acad. Nat. Sci. Phila., p. 386. 
Syn. Strotocrinus bloomfieldensis S. A. Minturn; 1879, Journ. Cincin. Soc. Nat. Hist., Plate 15, 
I i] 
Hib | 
f i Ng tat e e ° 
il ! i and interdistichal plates. 
a 
ih ' fr 
vik Ne yt : : 
h | il Strotocrinus regalis Hatt. 
KK i | Plate LXV. Figs. La, 6, ¢, d. 
f Ny iia HE 3 
i | "| | 1860. Actinocrinus regalis —Haut; Suppl. Geol. Rep. Lowa, p. 9. 
Fig. 6. 
An extremely large species, the calyx across the rim to the last bifur- / 
cation reaching sometimes a diameter of 12 cm., and a height from the foot ; 
of the basals to the base of the rim of 54 cm., and to the tips of the arms | 
about 15 cm. Dorsal cup urn-shaped, the sides a little convex; the distichals 
bending abruptly outward, and forming the base of the rim, which slopes 
a little upward. Tegmen almost flat, often depressed in the middle. Plates 
of the cup convex, covered with strong, angular ridges, which rarely meet 
in the centre of the plates, but run to a place near the centre, where they 
leave a small central depression or bare spot; sometimes, however, the 
middle space is occupied by a small transverse node. The ridges are in 
parallel sets of from three to six; there are five to six between the radials 
and basals, and from two to three between the other plates. The surface of 
the brachials in the rim is sharply elevated into angular, longitudinal, zigzag 
ridges, which distinctly mark the lines of bifurcation, and leave between 
them broad shallow grooves, which are paved at the bottom by the plates of 
the fixed pinnules. 
Basals very large, forming a deep cup, the sides of the plates beveled, 
